解决IDEA配置tomcat启动报错问题（idea运行tomcat一直报错）

在配置servlet不同路径时遇上以下两个错误：

java.lang.NoSuchMethodError: javax.servlet.ServletContext.getVirtualServerName()Ljava/lang/String；  java.lang.ClassNotFoundException: org.apache.jsp.index_jsp；

对于第一个问题，我上网查阅了很多资料后发现，可能是tomcat版本冲突导致，catalina log如下：

19-Feb-2018 08:26:44.175 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Server version:        Apache Tomcat/8.5.28 19-Feb-2018 08:26:44.175 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Server built:          Feb 6 2018 23:10:25 UTC 19-Feb-2018 08:26:44.175 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Server number:         8.5.28.0 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log OS Name:               Windows 7 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log OS Version:            6.1 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Architecture:          x86 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Java Home:             C:\Program Files\Java\jdk1.8.0_141\jre 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log JVM Version:           1.8.0_141-b15 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log JVM Vendor:            Oracle Corporation 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_BASE:         F:\apache-tomcat-8.5.28 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_HOME:         F:\apache-tomcat-8.5.28 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.util.logging.config.file=F:\apache-tomcat-8.5.28\conf\logging.properties 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djdk.tls.ephemeralDHKeySize=2048 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.protocol.handler.pkgs=org.apache.catalina.webresources 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dignore.endorsed.dirs= 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcatalina.base=F:\apache-tomcat-8.5.28 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcatalina.home=F:\apache-tomcat-8.5.28 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.io.tmpdir=F:\apache-tomcat-8.5.28\temp 19-Feb-2018 08:26:44.191 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent Loaded APR based Apache Tomcat Native library [1.2.16] using APR version [1.6.3]. 19-Feb-2018 08:26:44.206 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true]. 19-Feb-2018 08:26:44.206 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent APR/OpenSSL configuration: useAprConnector [false], useOpenSSL [true] 19-Feb-2018 08:26:44.830 信息 [main] org.apache.catalina.core.AprLifecycleListener.initializeSSL OpenSSL successfully initialized [OpenSSL 1.0.2m  2 Nov 2017] 19-Feb-2018 08:26:45.080 信息 [main] org.apache.coyote.AbstractProtocol.init Initializing ProtocolHandler ["http-nio-8080"] 19-Feb-2018 08:26:45.517 信息 [main] org.apache.tomcat.util.net.NioSelectorPool.getSharedSelector Using a shared selector for servlet write/read 19-Feb-2018 08:26:45.581 信息 [main] org.apache.coyote.AbstractProtocol.init Initializing ProtocolHandler ["ajp-nio-8009"] 19-Feb-2018 08:26:45.597 信息 [main] org.apache.tomcat.util.net.NioSelectorPool.getSharedSelector Using a shared selector for servlet write/read 19-Feb-2018 08:26:45.597 信息 [main] org.apache.catalina.startup.Catalina.load Initialization processed in 2422 ms 19-Feb-2018 08:26:45.643 信息 [main] org.apache.catalina.core.StandardService.startInternal Starting service [Catalina] 19-Feb-2018 08:26:45.643 信息 [main] org.apache.catalina.core.StandardEngine.startInternal Starting Servlet Engine: Apache Tomcat/8.5.28 19-Feb-2018 08:26:45.675 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [F:\apache-tomcat-8.5.28\webapps\docs] 19-Feb-2018 08:26:46.423 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [F:\apache-tomcat-8.5.28\webapps\docs] has finished in [748] ms 19-Feb-2018 08:26:46.423 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [F:\apache-tomcat-8.5.28\webapps\examples] 19-Feb-2018 08:26:47.059 严重 [localhost-startStop-1] org.apache.catalina.core.ContainerBase.addChildInternal ContainerBase.addChild: start:   org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/examples]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:752) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:728) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734) at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1141) at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1875) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Caused by: org.apache.catalina.LifecycleException: Failed to start component [Pipeline[StandardEngine[Catalina].StandardHost[localhost].StandardContext[/examples]]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5125) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 10 more Caused by: org.apache.catalina.LifecycleException: Failed to start component [org.apache.catalina.authenticator.FormAuthenticator[/examples]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) at org.apache.catalina.core.StandardPipeline.startInternal(StandardPipeline.java:182) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 12 more Caused by: java.lang.NoSuchMethodError: javax.servlet.ServletContext.getVirtualServerName()Ljava/lang/String; at org.apache.catalina.authenticator.AuthenticatorBase.startInternal(AuthenticatorBase.java:1186) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 14 more 19-Feb-2018 08:26:47.075 严重 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Error deploying web application directory [F:\apache-tomcat-8.5.28\webapps\examples]  java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/examples]] at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:756) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:728) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734) at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1141) at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1875) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)

我先试着删除其他Tomcat版本，重新配置tomcat环境变量并重新部署Tomcat。发现并没有解决问题，再次上网查阅，发现getContextPath()在servlet2.5特有。于是试着删除原先jar包中的servlet-api.jar,然后重新部署项目。发现了第二个问题，log如下：

19-Feb-2018 09:59:51.534 严重 [http-nio-8080-exec-3] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [jsp] in context with path [/Happy] threw exception [java.lang.ClassNotFoundException: org.apache.jsp.index_jsp] with root cause  java.lang.ClassNotFoundException: org.apache.jsp.index_jsp at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:129) at org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:60) at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:159) at org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:171) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:380) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) 19-Feb-2018 10:03:45.289 严重 [http-nio-8080-exec-1] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [jsp] in context with path [/Happy] threw exception [Unable to compile class for JSP] with root cause  java.lang.ClassNotFoundException: com.sun.el.ExpressionFactoryImpl at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1291) at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1119) at javax.el.FactoryFinder.newInstance(FactoryFinder.java:83) at javax.el.FactoryFinder.find(FactoryFinder.java:193) at javax.el.ExpressionFactory.newInstance(ExpressionFactory.java:185) at javax.el.ExpressionFactory.newInstance(ExpressionFactory.java:156) at org.apache.jasper.compiler.PageInfo.(PageInfo.java:80) at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:117) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:374) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:351) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:335) at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:595) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:368) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748)

再次查阅资料，发现是缺少jar包。因为jdk1.8的扩展jar包里没有servlet相关api，故IDEA会导入失败。

此时需要导入jar包，之前我是下载相关api

然后放到下图目录中

为了防止出现缺少jar包问题，建议直接去tomcat目录下的lib中找到servlet-api.jar，直接复制到ext中。然后再重新部署一下tomcat，问题解决。

总结